Catching up on our 2021 major upgrades
Skookum’s new solar panels, satellite dome and communications antennas on top of our new stainless steel arch.
Life from May to July was busy, in my opinion, way too busy. Stepping out of life on land was meant to be moving away from rushing through the week, getting from one commitment to another, but boat life from March to July was strangely quite scheduled. All of this is our choosing, of course, so no complaints at all; more, an observation that one of our goals for this phase of life was to move more slowly, yet it hasn’t quite been realized. The primary source of the haste were four boat projects that all coincided in June.
The boat buying process normally involves a survey by a qualified surveyor to clarify the condition of the boat and identify any necessary and/or desired repairs and upgrades. We knew from our survey that there were several essential and desirable improvements that we wanted to make to the boat, but our plan was to spend a few months living with the boat in its current form before we started to tackle the larger items.
That probably lasted a week…which is normal for us.
Watermaker Upgrade
When we got to Santa Rosalia in February, we fired up the existing Spectra 10 gallon per hour watermaker to make our first tank of potable water. A watermaker desalinates and purifies sea water to make it suitable for drinking. It’s a reverse osmosis process where the water is squeezed through a membrane at high pressure and only the fresh water, stripped of all dissolved solids (salt) and impurities is trapped by the membrane and discharged back overboard. We filled one tank successfully, although the production was slow – we were getting about 8 gallons per hour output, so it took a 10-hour run time to fill one of our two 80-gallon tanks. Watermakers are typically loud when they run, so if we’re going to run it, it’s more desirable to have a high-capacity unit that we only have to run for a short period of time to fill our tanks.
On our second or third use we noticed a leak on the side of the primary pump and there was salt in the output water; closer inspection suggested a failed o-ring. We replaced that twice and tested both times, but concluded it was a deeper issue. We talked about it and agreed that upgrading the unit made more sense than repairing it, so we started shopping. Our friends Jamie and Behan on Totem recommended a Cruise RO watermaker sold by Rich Boren who happens to be located in La Paz, Mexico; so we ordered the unit and planned to pick it up in La Paz, since we knew we’d be getting there soon enough.
As is very common on boats, one upgrade requires another or, often, many others. In our case the 40 gallon per hour watermaker that we chose needed more electrical current on startup than our 1800w inverter and AGM batteries could handle, so choosing the high-capacity unit required a power upgrade to support it. We had already anticipated this and had been researching inverters, solar panels, charge controllers and lithium batteries since we purchased the boat. We sailed to La Paz in April to collect the watermaker from Rich and scope out options for the electrical upgrades.
Electrical Upgrade
Our number one priority was to be as 100% off-grid (and therefore not reliant on on-shore amenities) as possible, with a solar array that was large enough to put into the batteries all of the energy we would need to use overnight when the sun wasn’t shining. One excellent attribute of a catamaran is that we have a big footprint compared to a monohull – our boat is 21’ wide – and we wanted to maximize that benefit by installing the largest solar array we could fit. I met with Omar at Tecnosol in La Paz to price solar panels and chose four 440 watt Sharp panels, which when added to our three 175 watt panels created a 2285 watt array. My basic calculation was that we would achieve 75% potential for five hours per day giving us about 8,500 watts per day or 714 amps at 12 volts.
The ability to generate the power is useless unless you can store it, so the battery bank was the next step. Our existing batteries were three 4D AGM (absorbed glass matt) batteries each capable of storing 220 amp-hours (AH) at 12 volts. You can typically deplete AGM batteries to 50% of their total capacity before you risk damaging the cells and degrading the batteries’ capacity to store charge. Thus, our bank of 3 AGMs gave us 330 amp-hours of usable energy before we needed to recharge them. In addition, different battery compositions receive charge at different rates, and we had found in our experience that our batteries could only take in about 40 amps regardless of how much current was available to them, so our 330 amps would take about 8 hours to recharge at max input current. That led us, among other things, to consider upgrading our batteries to lithium.
Lithium batteries are relatively new in the boating world, but very widely used outside of boats. Your cell phone, camera, smart watch, and most electric cars all use a version of lithium batteries. The big benefits of lithium for our case is that they can handle very rapid charging and discharge cycles and can be discharged to only 10% capacity remaining without damaging the cells. So if our new solar array could put out around 150 amps in the middle of the day then the lithium battery could take all of that current and store it for use later. Compared to the example above, the 330 AH depleted from the bank overnight could be replaced in just 2.2 hours.
The other advantage of lithium is that the density of the batteries is much greater, so you get more amp-hours per battery for the same physical size. We replaced our three 220AH AGM batteries with four 280AH LiFePo4 batteries, increasing our total usable capacity by over 700 AH, but taking up less space than the old batteries. One of the hesitations boaters have with lithium batteries are their cost, and we had spent several weeks considering the various lithium battery suppliers such as ReLion or BattleBorn. We were prepared to spend the money on one of those brands because of the massive benefit that the fast charging and deep discharge characteristics of lithium offer, but it was certainly a high price tag, over $12,000 USD for the BattleBorns.
While anchored in Agua Verde we met another cruiser who had installed a pair of lithium batteries from Rich Boren’s company, lithiumbatterykit.com. He was very happy with the performance of the batteries and convinced me to explore further. Each battery contains four 3.3v EVE cells, a 300A fuse, and a 120A Overkill Solar battery management system contained within a standard Group 27 battery box. The BMS ensures that the four cells remain balanced and protects the battery from over charging or rapid discharging in a short circuit situation. The cells have a 5-year warranty, although like most warranties you have to ship the defective product back to the manufacturer, and the BMS gets good independent reviews. In the end we concluded that even if these batteries weren’t quite as durable as the more established companies (I have no reason to assume they won’t be, but was making a risk/benefit calculation on purchasing from a lesser known company), they were unlikely to be three times worse, and thus we could replace them twice and still have spent less than the cost of the BattleBorns. We ordered four 280AH units, which Rich delivered to us at the marina in La Paz.
Once we cracked the question of how to generate the energy, and how to store it, the final question was how we would use the energy. That took us to inverter selection. An inverter takes the direct-current 12-volt electricity stored in our batteries and converts it 110v alternating current that our normal household appliances and electronics need. Think of all the day to day things that use electricity in your life – laptop, phone charger, tv, food processor, Vitamix, Instapot. All of these (in North America) run on 110-120v alternating current and if we want to run them on the boat, we have to invert the 12v from our batteries to 110v. The search for the perfect inverter began… (and yes, we do have a Vitamix and Instapot….we’re not roughing it THAT much!)
My dream scenario when planning the project was that we could install a system that had the capacity to run one of our air conditioning (AC) units. These not only require 110v, but are also quite large power consumers, and so the size of the inverter required to run them was a factor. Inverters are sized in watts, and my napkin math told me (which I double-checked by trolling Youtube for someone else to verify it) that I could run one from a 3KW (3000 watt) unit, but that a 5KW unit would give us a little more headroom, enabling us to run an AC unit and other loads simultaneously. I like the simplicity of using multiple devices from the same manufacturer, especially when it increases the ‘smarts’ of the system; something that we’ve always done in our home renovations where possible. For the boat we chose Victron. I really like the quality and reliability of Victron products, and they offered everything we needed: inverter, solar charge controllers, battery monitor; and even had a hub that enables us to view the status of all components simultaneously and feed in senders that could report on our fuel and water levels in our tanks.
We have three main energy draws on the boat: our fridge/freezer, watermaker, and air conditioners – we have two AC units, one for each hull (side of the boat). Our fridge/freezer draws about 8 amps when running, and in the heat of the summer months pretty much runs 24 hours a day. Our watermaker has both a 12v DC boost pump and a 110v AC high pressure pump. When both pumps are running it’s consuming about 125 amps. Our air conditioners consume 13-15 amps @ 110v, so that’s about 120 amps each when running on the inverter. As we sized up our needs, and the possibility of us adding other electric items to the boat in future, including possibly an electric oven, we felt that the 5KW inverter was the right choice.
I reached out to a few Victron vendors with mixed results. Generally, if you’re doing a 12v project on a boat it’s definitely a DIY job and there is very low risk of electric shock. When you’re inverting to 110v or 220v it starts to get a little more complicated and the risks are higher, and so we felt having some professional oversight of the project was a good idea. After several dead-ends I found a great Victron-certified installer in Puerto Vallarta, Pieter Karsten of Marine Vallarta. Pieter provided hours of telephone and email support, helping me confirm the specifications of the build so that he could ship the parts to La Paz prior to flying over to meet us. Pieter arrived at the end of June and we did a pretty intense 8 day install to get everything complete.
Stainless Upgrade
While I was completing the electrical install with Pieter, another job was taking place in parallel on the boat. Sergio Gallindo from La Paz Stainless and Welding was installing a custom stainless structure on the back of the boat to hold the new solar panels, life raft, stern anchor, antennas, and to replace our dinghy davits. It is no exaggeration to say Sergio is an artist and he and his crew were amazing to work with. He designed a structure that not only created a very solid platform for the panels and davits, but that looks aesthetically pleasing also. It was a big project and people would stop on the dock every day to admire the structure and talk about design. Sergio was a total pleasure to deal with, and we’re extremely happy with the result.
Rigging Upgrade
Finally, we tackled one more job whilst in La Paz, our standing rigging. Most sailboat masts are held up by wire rigging that runs from the top of the mast to fittings on the deck or topsides. In our case, as a catamaran, we have a forestay that holds the roller furler for the genoa (the sail at the front), shrouds that go from the top of the mast down to each side, and diamond stays that stiffen the mast. Wire rigging can last for over twenty years, but it is common for marine insurance providers to require replacement after ten. Recommended by the cruising club in La Paz, Luis and Sergio of Dawn Rigging did an incredible job replacing the rigging while we were docked in La Paz.
Do you run air conditioning from your batteries, bro?
The results of all this effort have been brilliant. We typically make water about once a week and can fill one of our 80-gallon tanks in about 2-1/2 hours. We often do laundry on water making days also – did I mention we added a washing machine to Skookum? – which is somewhere between a necessity and a luxury. Two kids under four make a LOT of laundry, especially as Ellie likes to wear no less than three different outfits every day. Although Lily is normally naked 24/7, so that probably offsets some of Ellie’s consumption. We have so much water that I’ve decided to fit a fresh water washdown hose on the deck so that we can wash the boat while at anchor, a luxury often seen only on the fancy yachts.
The electrical upgrades have been even more profound. The Sea of Cortez has been extremely hot since June. The temperature is typically in the mid 30s every day, though we’ve definitely seen 40 degrees Celsius. The water temperature was 38 degrees on one of the last days we swam, so jumping off the boat for a swim doesn’t even cool you down. Since completing the install we have been able to run one of our two AC units all night, keeping our bedroom temperature at a very comfortable 26 degrees. Typically, we turn it on at about 5:30pm or so when we start cooking dinner. We run the port side to cool the girls’ hull down and put them to bed at 7:30pm. Then we switch to the starboard unit to cool our bedroom, leaving it on all night. Depending on the outside temperature our batteries have been as high as 35% remaining or as low as 12% remaining by the next morning, and our solar array charges them fully by about 2pm the next day. We have only run our generator once for 2 hours since leaving La Paz and otherwise have been 100% reliant on solar to supply all our electricity needs. It feels pretty incredible to be eliminating our reliance on fossil fuels and relying entirely on renewable energy for our at anchor power consumption. The next frontier is swapping out our diesel engines for electric motors, but I think that’s probably a project for different boat.
In all it took just over a month to complete all the work and we sailed out of La Paz on July 13th bound for Espiritu Santo and beyond. A huge step forward in the life of the boat, and many ticks off the to-do list in terms of making Skookum fit for purpose for our power-hungry, water-thirsty family.
*I’m finally posting this on Jan 2nd, 2022 - I know! #facepalm. We haven’t burned fossil fuel to make electricity once since July 16th 2021, which feels like an incredible validation of the off-grid upgrades.